The Glenmore Place Apartments in Clifton Heights, where Mercy Fitzgerald shooting suspect Richard Plotts resided, is shown. Delaware County District Attorney Jack Whelan said Tuesday that investigators recovered a gun manufactured in the 1920s in Plotts’ apartment on Friday, one day after the psychiatric patient is accused of killing his caseworker and injuring his doctor with a revolver from the 1940s. (Special to the Times / Pete Bannan)

MEDIA — Investigators have determined that one of the weapons found in the apartment of the man charged in the deadly hospital shooting last week was a functioning, .25-caliber, semiautomatic firearm manufactured nearly a century ago.

The weapon was one of two seized during the search of Richard S. Plotts’ Clifton Heights apartment following the shooting, Delaware County District Attorney Jack Whelan said Tuesday.

“We just learned the one gun was a starter pistol, however, the second gun was a .25-caliber, semiauto firearm, which was capable of functioning,” he said. “We believe it was probably manufactured between 1920 and 1925.”

The two weapons, and the starter pistol, which also is old, are in very good condition.

“They are extremely old, bordering on antiques, but in very good shape, very well maintained,” Whelan said. “The murder weapon almost looked newish.”

Plotts, 49, is charged with the fatal shooting of 58-year-old Hunt and injuring psychiatrist Dr. Lee Silverman at Mercy Fitzgerald Hospital’s Sister Marie Lenahan Wellness Center in Yeadon on Thursday. Authorities said Plotts was standing next to Hunt, across the desk from Silverman, when he pulled out the .32-caliber revolver and shot Hunt point blank in the head.

Silverman also was armed and shot back, seriously injuring Plotts.

Whelan said Silverman told detectives that he had emptied his gun, a .32-caliber semiautomatic Seecamp, which holds one bullet in the chamber and six in the clip.

“We believe 12 shots were fired that day,” he said.

Caseworker John D’Alonzo and Dr. Jeffrey Dekret were able to get the gun from Plotts and wrestle him to the ground.

Hunt, of Philadelphia, was pronounced dead at the scene. Silverman suffered a hand injury and a graze wound to his head. He is recovering at home.

If the psychiatrist had not been armed and returned fire, Whelan believes Plotts, who had an additional 39 bullets on him at the time, would have continued to shoot others inside the office building.

“But for the actions of Dr. Silverman and the staff, we’d probably have more decedents. More people killed,” he said during a press conference on Friday.

Plotts, a convicted felon, is prohibited from possessing a firearm.

Investigators are finding it difficult to trace the .32-caliber Iver Johnson and the .25-caliber semiautomatic Plotts had in his possession because of their age. Whelan noted that requirements for gun ownership back in the ’40s were vastly different.

Investigators’ attempts to trace the Iver Johnson have returned no results. They are now attempting to trace the semiautomatic weapon.

“It’s functional and we are in the process of seeing if we can trace it,” he said.

Whelan said it is unusual to find shooters using old or antique weapons in modern day crime scenes.

“This is very rare to see these types of older weapons used in any type of homicide case,” Whelan said. “Typically, you’ll see .40-caliber or millimeter-type of weapons in most of these shootings.”

The weapon used in the hospital shooting also was unusual in that it is a revolver and has to be reloaded, he added.

Investigators also seized a computer from Plotts’ home on Friday. They are in the process of obtaining a search warrant to conduct a forensic analysis of the computer.

Plotts, who has a history of mental illness, remains hospitalized, under guard, at the Hospital of the University of Pennsylvania in Philadelphia. Over the weekend, a Philadelphia judge arraigned him at his bedside on a number of charges including first-degree murder.

As soon as he is medically released, he will be transported to Delaware County where he’ll be arraigned by a county magisterial district judge and sent to the county jail to await a preliminary hearing.

Funeral services for Hunt are scheduled for Wednesday at the John Stretch Funeral Home, 236 East Eagle Road, Haverford. Visitation is from 6-8 p.m. with a service to follow at 8 p.m. Burial is Aug. 1 at Riverview Cemetery, Hancock, N.Y.